1. Field of the Invention
The invention herein pertains to the field of flowable herbicides, materials and processes for preparation thereof. In particular, flowable herbicides comprising acetanilides, e.g., propachlor, and mixtures thereof with triazines, e.g., atrazine, and appropriate emulsifying/suspending agents, solvents and carriers are disclosed.
2. Description of the Prior Art
The prior art with respect to herbicides comprises wettable powders (WP's) emulsifiable concentrates (E.C.'s), granules and flowable formulations which may be prepared as package mixes or tank mixes.
As relevant to the present invention which pertains to flowable herbicides comprising certain 2-haloacetanilides alone or in combination with certain s-triazines, the prior art describes a variety of formulations in the above forms. For example, U.S. Pat. No. Re. 26,961 (original U.S. Pat. No. 2,863,752) and U.S. Pat. Nos. 3,442,945 and 3,547,620 describe various 2-haloacetanilides, e.g., propachlor, alachlor, butachlor, etc., which may be used alone or in admixture with herbicides including various triazines, including s-triazines. U.S. Pat. Nos. 2,891,855 and 2,909,420 describe various triazines, e.g., atrazine, and Canadian Pat. No. 847,250 refers to the combination of certain s-triazines with alachlor in various forms, e.g., solutions, emulsions, suspensions, or dusts. However, this patent does not give any details as to the materials (except active ingredients) or processes for producing any of these forms of formulations.
In addition to the above patent literature, there are commercial formulations of flowable propachlor and flowable atrazine which are applied as tank mixes.
The above prior art, the most relevant known to the inventors, is devoid of any disclosure or other description of a unitary flowable herbicide comprising a 2-haloacetanilide, e.g., propachlor or alachlor, and an s-triazine, e.g., atrazine. The commercial flowable propachlor and flowable atrazine mentioned above are each of proprietary composition, hence, unknown to the inventors. In addition, these flowable herbicides must be prepared separately, packaged separately, transported and stored in separate containers and used as a tank mix. As will be shown below, the flowable propachlor of this invention has superior properties as an independent flowable herbicide, i.e., having only one active ingredient, vis-a-vis said commercial flowable propachlor.
Problems associated with prior art forms of acetanilide and/or s-triazine formulations include the need to convert wettable powder forms of these solid materials into slurries to be used by the farmer in preparing tank mixes for application to the soil. The preparation of slurries of wettable powders of some herbicides, e.g., of prominent note is propachlor, presents certain safety hazards and inconveniences due to the generation of noxious dusts which are irritable to the skin and hazardous to breathe. In addition, wettable powders of propachlor and atrazine when prepared as tank mixes do not disperse well, have poorer spontaneity of "bloom", have lower suspensibility, poor redispersibility and poorer compatibility with liquid fertilizers than do liquid formulations such as emulsifiable concentrates and flowable formulations.
Water-based flowable herbicides have advantages over emulsifiable concentrates since the latter generally required organic solvents which are usually flammable and/or of toxic composition, hazardous to the skin or from vapors evolved therefrom. Flowable herbicides do not suffer the usual disadvantages of wettable powders, dusts and emulsifiable concentrates mentioned above, are easier to prepare and use and have the same, and sometimes superior, herbicidal efficacy and crop safety as older forms of formulation mentioned above. Moreover, flowable herbicides generally, and in the present invention specifically, have superior properties with respect to suspensibility, viscosity, bloom, redispersibility, stability (e.g., shelf-life and temperature cycling) and compatibility with liquid fertilizers.
It is a particular advantage of the present invention to provide a combination flowable herbicide comprising a 2-haloacetanilide and an s-triazine, e.g., flowable propachlor and atrazine, which may be prepared, transported, stored and used as a one-container herbicide having none of the disadvantages of prior art herbicides and all of the advantages mentioned hereinabove.
As used herein and in the art a "flowable herbicide" denotes a suspension of solid particles in a liquid carrier.